ARCC 1202 Study Guide - Quiz Guide: Precast Concrete, 3D Printing, Henry Bessemer
7 Jun 2018
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History of Structures Exam 2
History of Concrete:
Concrete was discovered by the ancient Romans while quarrying limestone for mortar on the slopes
of Mount Vesuvius. They accidentally discovered a silica-and alumina-bearing mineral that, when
mixed with limestone and burned, produced a cement that exhibited a unique property: When
mixed with water and sand, it produced a mortar that could harden underwater as well as in the air.
This mortar was stronger, harder, much more adhesive, and cured much quicker than the ordinary
lime mortar to which they were accustomed. The subsequent acquired knowledge of concrete
construction was lost with the fall of the Roman empire.
o In 1824, Joseph Aspdin patented an artificially produced cement
that he named Portland cement, after English Portland limestone.
Reinforced Concrete: Concrete in which steel bars are embedded to resist tensile forces. Developed
in the 1850’s by several people:
o In France, J. L. Lambot built several concrete boats (1854).
o In America, Thaddeus Hyatt tested reinforced concrete beams.
o Joseph Monier, a French gardener, invented reinforced
concrete in 1867when he made flower pots and tubs of
concrete reinforced with an iron mesh. Besides his pots and
tubs, he promoted reinforced concrete for use in railway
ties, pipes, floors, arches, and bridges.
o In the 1920’s, Eugene Freyssinet established a scientific basis for the design of pre-stressed
concrete structures.
Curing process, heat of hydration, air entrainment, admixtures, slump tests
Pre-stressed concrete structures are produced by mixing coarse and fine aggregates, Portland
cement, and water, and allowing the mixture to harden. During this hardening process (called the
curing process), considerable heat (heat of hydration) is given off as the cement combines
chemically with water to form strong crystals that bind the aggregates together. During the curing
process, as excess water evaporates from the concrete due to the generated heat, the concrete
shrinks slightly.
Concrete Admixtures / High-range water-reducing or Superplasticizers : Organic compounds that
transform a stiff concrete mix into one that flows freely into the forms. They are either used to
facilitate placement of concrete under difficult circumstances or to reduce the water content of a
concrete mix in order to increase strength.
(Also used in Self Consolidating Concrete)
Air-entraining admixtures increase the workability of the wet concrete,
reduce freeze-thaw damage, and, when used in large amounts, create very
lightweight non-structural concrete with thermal insulating properties.
Water-reducing admixtures allow a reduction in the amount of mixing water while retaining the
same workability, which results in a higher strength concrete.
Accelerating admixtures cause concrete to cure much faster.
Retarding Admixtures slow the curing of concrete to allow more time for working with the wet
concrete.
Coloring agents: Dyes and pigments used to alter and control the color of concrete for building
components whose appearance is important.
Concrete Slump Test:
Ball Penetration Slump Test:
Document Summary
Concrete was discovered by the ancient romans while quarrying limestone for mortar on the slopes of mount vesuvius. This mortar was stronger, harder, much more adhesive, and cured much quicker than the ordinary lime mortar to which they were accustomed. The subsequent acquired knowledge of concrete construction was lost with the fall of the roman empire. In 1824, joseph aspdin patented an artificially produced cement that he named portland cement, after english portland limestone. Reinforced concrete: concrete in which steel bars are embedded to resist tensile forces. In france, j. l. lambot built several concrete boats (1854). In america, thaddeus hyatt tested reinforced concrete beams. Joseph monier, a french gardener, invented reinforced concrete in 1867when he made flower pots and tubs of concrete reinforced with an iron mesh. Besides his pots and tubs, he promoted reinforced concrete for use in railway ties, pipes, floors, arches, and bridges.
